Possibilities of the Guard Ring for Electrical Signal Confinement in the Polarization Measurements of Reinforcements

Abstract

The technical possibilities of the “guard ring” for the local measurement of polarization resistance (Rp) are analyzed for the purpose of determining the corrosion rate of rebar in large reinforced concrete structures. Based on tests carried out with reinforced concrete slabs as well as with an electrical analogue, it is concluded that the supposed confinement capacity of the electrical signal under the central counterelectrode is nearly guaranteed only in the event of low Rp values. On the other hand, with high Rp values, the electrical signal can extend way beyond the guard ring itself.